Juno Spacecraft in Safe Mode for Latest Jupiter Flyby. Scientists Intrigued by Data from First Flyby.

This
composite image depicts Jupiter’s cloud formations as seen through the eyes of
Juno’s Microwave Radiometer (MWR) instrument as compared to the top layer, a
Cassini Imaging Science Subsystem image of the planet. The MWR can see a couple
of hundred miles (kilometers) into Jupiter’s atmosphere with its largest
antenna. The belts and bands visible on the surface are also visible in
modified form in each layer below.

Image credit:
NASA/JPL-Caltech/SwRI/GSFC

NASA’s
Juno spacecraft entered safe mode Tuesday, Oct. 18 at about 10:47 p.m. PDT
(Oct. 19 at 1:47 a.m. EDT). Early indications are a software performance
monitor induced a reboot of the spacecraft’s onboard computer. The
spacecraft acted as expected during the transition
into safe mode, restarted successfully and is healthy. High-rate data has been restored, and the
spacecraft is conducting flight software diagnostics. All instruments are off,
and the planned science data collection for today’s close flyby of Jupiter
(perijove 2), did not occur.

“At
the time safe mode was entered, the spacecraft was more than 13 hours from its
closest approach to Jupiter,” said Rick Nybakken, Juno project manager from
NASA’s Jet Propulsion Laboratory in Pasadena, Calif. “We were still quite a
ways from the planet’s more intense radiation belts and magnetic fields. The
spacecraft is healthy and we are working our standard recovery procedure.”

The spacecraft is designed to enter safe mode if its
onboard computer perceives conditions are not as expected. In this case, the
safe mode turned off instruments and a few non-critical spacecraft components,
and it confirmed the spacecraft was pointed toward the sun to ensure the solar
arrays received power.

Mission managers are continuing to study an
unrelated issue with the performance of a pair of valves that are part of the
spacecraft’s propulsion system. Last week the decision was made to postpone a
burn of the spacecraft’s main engine that would have reduced Juno’s orbital
period from 53.4 to 14 days.

The
next close flyby is scheduled on Dec. 11, with all science instruments on.

The Juno science team continues to analyze returns
from the first close flyby on Aug. 27. Revelations from that flyby include that
Jupiter’s magnetic fields and aurora are bigger and more powerful than
originally thought. Juno’s Microwave Radiometer instrument (MWR) also provided
data that give mission scientists their first glimpse below the planet’s swirling
cloud deck. The radiometer instrument can peer about 215 to 250 miles (350 to
400 kilometers) below Juno’s clouds.

“With the MWR data, it is as if we took an onion
and began to peel the layers off to see the structure and processes going on
below,” said Bolton. “We are seeing that those beautiful belts and bands of
orange and white we see at Jupiter’s cloud tops extend in some version as far
down as our instruments can see, but seem to change with each layer.”

The JunoCam public outreach
camera also was operating during the Aug. 27 flyby. The raw images from that
flyby (and all future flybys) were made available in the JunoCam section for the public to not only peruse but to process
into final image products. JunoCam is the first outreach camera to venture
beyond the asteroid belt.

“JunoCam
has a small operations team and no image processing team, so we took a leap of
faith that the public would step up and help us generate images of Jupiter from
the raw data,” said Candy Hansen, JunoCam imaging scientist from the Planetary
Science Institute in Tucson, Arizona. “All sorts of people are coming to the
JunoCam site and providing their own aesthetic. We have volunteers from all
over the world, and they are doing beautiful work. So far all our expectations for
JunoCam have not only been met but are being exceeded, and we’re just getting
started.”

The
final image products include straightforward images of the solar system’s
largest world, but also some with a certain artistic license, including a
variation on Vincent Van Gogh’s Starry Night painting and even a “smiley face”
made from an image of Jupiter’s south pole. These amateur-generated JunoCam
images are not only being used to help interest the media and public in this
mission to the most massive planet in the solar system, but are engaging Juno’s
science team as well.

“The
amateurs are giving us a different perspective on how to process images,” said
Hansen. “They are experimenting with different color enhancements, different
highlights or annotations than we would normally expect. They are identifying storms tracked from Earth
to connect our images to the historical record. This is citizen science at its
best.”

The Juno spacecraft launched on Aug. 5, 2011, from
Cape Canaveral, Florida, and arrived at Jupiter on July 4, 2016. During its mission of exploration, Juno soars low over
the planet's cloud tops -- as close as about 2,600 miles (4,100 kilometers).
During these flybys, Juno will probe beneath the obscuring cloud cover of
Jupiter and study its auroras to learn more about the planet's origins,
structure, atmosphere and magnetosphere.

Juno's name comes from Roman
mythology. The mythical god Jupiter drew a veil of clouds around himself to
hide his mischief, and his wife – the goddess Juno – was able to peer through
the clouds and reveal Jupiter's true nature.

JPL manages the Juno mission for the principal
investigator, Scott Bolton, of Southwest Research Institute in San Antonio.
Juno is part of NASA's New Frontiers Program, which is managed at NASA's
Marshall Space Flight Center in Huntsville, Alabama, for NASA's Science Mission
Directorate. Lockheed Martin Space Systems, Denver, built the spacecraft.
Caltech in Pasadena, California, manages JPL for NASA.

This image of the sunlit part of Jupiter and
its swirling atmosphere was created by a citizen scientist (Alex Mai) using data
from Juno’s JunoCam instrument. JunoCam’s raw images are available in the Processing Section for the public to peruse and process into image products.

A smiley face can be seen in this image of
Jupiter created by a citizen scientist (Randy Ahn) using data from Juno’s
JunoCam instrument. In JunoCam’s view, Jupiter is only half-lit, so Ahn copied
and flipped the half-smile to make a full smile out of Jupiter’s swirling
atmosphere. JunoCam’s raw images are available in the Processing Section for the public to peruse and process into image products.